short-tailed aphideater

Short-tailed aphideater is a small, wasp-mimic, hover fly. It occurs in the United States and southern Canada east of the Great Plains. The larvae feed on aphids. Adults are found from mid-May to late October both in forests and in open habitats. They feed on flower nectar.

Adults are ¼″ to ½″ (6.8 to 12.0 mm) long. Females of this species cannot be distinguished from Eupeodes fumipennis and E. americanus.

The head is wider than the thorax. There are two large compound eyes on the sides of the head and three small simple eyes (ocelli) in a triangle on top of the head. The compound eyes are bare, with no erect hairs. On the male they meet at the top of the head. On the female they do not. The face is mostly yellow but has a brown stripe in the middle. The stripe may be broad and distinct or narrow and obscure. There are also two semicircular, pale brown to black spots above the bases of the antennae. The cheek is usually entirely yellow, rarely brownish toward the front and rear. The protruding mouthpart (proboscis) is short and fleshy. The antennae are short and have just three segments. On the third segment there is a stiff, forward-pointing bristle (arista).

The thorax is large, shiny, and black. It is covered with short, erect, yellow hairs, densely on the sides, sparsely above. The exoskeletal plate between the abdomen and thorax (scutellum) is large, rounded, dull yellow, and translucent. It is covered with pale yellow hairs above and has a moderately dense fringe on the rear margin.

The abdomen is longer and broader than the thorax, oval when viewed from above, and nearly flat when viewed from the side. It is black with bright yellow markings. There are five visible segments. On the male, segment 1 is very narrow and entirely black. Segment 2 has a pair of large spots that almost reach the lateral margins. On most individuals the spots are distinctly separated in the middle. On some individuals, they meet in the middle. Segments 3 and 4 each have a broad yellow band that does not quite reach the lateral margins. The forward margin of the band is nearly straight, the rear margin is nearly straight or shallowly concave in the middle. Segment 4 has a broad stripe on the rear margin. Segment 5 is yellow with a narrow black band. On the male the claspers on the genitalia are short.

The legs are mostly yellowish-orange. The first segment of each leg (coxa) is black. The base of the third segment (femur) of the front and middle legs is brown to black. The femur on the hind leg is slender, not thickened, and is brown to black on the basal half to basal four-fifths. On each leg the fourth segment (tibia) and the last part of the leg (tarsus), corresponding to the foot, are often brownish.

The wings are clear and are mostly covered with short erect hairs. The lobe attached to the base of the wing (alula) is broad and is itself wing-like. The inner third of the alula is bare, with no hairs. There is a spurious vein between the radius (R) and media (M) veins. The anal cell is long and is closed near the wing margin. The marginal, R₅, and M₂ cells are also closed. The R₄₊₅ vein is nearly straight.

Total length: ¼″ to ½″ (6.8 to 12.0 mm)

American hover fly (Eupeodes americanus) adult male surstyli are long and twisted, but they are otherwise identical. Females are indistinguishable.

Forests and open habitats

Two generations per year: Mid-May to late October

Aphids

Flower nectar

Sources

24, 29, 30, 82, 83.

Short-tailed Aphideater larva eating aphids (Eupeodes pomus)
brian0918

Location: Woodbury, MN

Location: Woodbury, MN